Stihl 039 has stripped bar stud - how to fix it?

[thaugen]

When I bought this saw the seller told me the rear bar stud was stripped. The saw has been working fine but now I want to put a new chain on it. I haven't had it apart yet because I still need to use it, but when I tighten on the 19mm nut it spins on the stud. Is the stud easily replaceable? Instructions?

Thanks in advance, Tom

 

[Fish]

It threads into the bottom engine pan, lock it in a bench vise to get it started.

 

[thaugen]

OP replies:

It threads into the bottom engine pan, lock it in a bench vise to get it started.

Fish, thanks for the reply. I assume you mean lock the saw in a vise? By any chance is the stud left-threaded on the bottom?

Ordinarily I would jam two nuts onto the stud and then twist the bottom one with a wrench to back out the stud, but since this stud is stripped, I assume there won't be sufficient good threads to do that. Do you think Vice-grips would loosen the stud or do I need a special tool? Alternative: weld the nut onto the stud, then twist the nut?

 

[jus2fat]

If..."the nut spins on the stud"..that means the visible threads on the stud are stripped.

Are you really saying the whole stud bolt spins or just the nut..??

J2F

 

[thaugen]

If..."the nut spins on the stud"..that means the visible threads on the stud are stripped.

Are you really saying the whole stud bolt spins or just the nut..??

J2F

The stud stays stationary and the nut spins on the stud. Since I haven't taken it apart yet, I assume the threads within the nut and stud are bunged up. The threads visible just to the outside of the nut look OK so I assume someone over-tightened the nut rather than cross-threading or other foolishness.

Tom

 

[jus2fat]

Well..this sounds good..I suspect the stud threads are stripped and not the nut threads.

You can't know until you remove the bar.

You can then just easily replace the bar stud (or nut) as needed. No special tools required.

J2F

 

[Fish]

Double nutting is also kinda foolishness....

 

[thaugen]

Double nutting is also kinda foolishness....

Fish, I assume you are referring to my removal method of threading two nuts onto the stud and then wrenching the bottom one to turn the stud out? What other method would be used to turn the stud?

Tom

 

[Fish]

Double nutting boogers the threads on the stud and nuts.....

Period..............

 

[Whiskers]

If the stud threads are already screwed up get a set of vice grip and unscrew the thing. Or, if you don't want to mess the stud up anymore, a rag can be put over the stud to protect the thread when the vice grips are used.

 

[Fish]

If the stud threads are already screwed up get a set of vice grip and unscrew the thing. Or, if you don't want to mess the stud up anymore, a rag can be put over the stud to protect the thread when the vice grips are used.

Is this a kevlar rag?

 

[Whiskers]

Wasn't a single layer rag, basically a wadded up rag around the stud. Just did it on my 029 super and i worked like a charm. Backed the stud out until I could get a good grip on the collar.

 

[thaugen]

Fish, what tools/technique would you use to unscrew the stud from the saw?

Thanks, Tom

 

[redoakneck]

How much of the stud (collar screw) is sticking out past the nut? Might be hard to get a good grip on it if it is only sticking out 3/16" or less. I have slotted the end of broken bolts with a dremel cutting wheel and then used a T-handle screw driver to unscrew them. I think those are regular thread so twist it out CCW. Not sure if a little heat with a heat gun would help or not, might char yer paint. I can see the OP point that if that nut is close to the end of the stud you got nothing to grab with vise grips.

 

[Fish]

Fish, what tools/technique would you use to unscrew the stud from the saw?

Thanks, Tom

A huge black bench vise with a deep voice.......

 

[thaugen]

A huge black bench vise with a deep voice.......

So Fish, I politely ask for help (first-time poster), then after you reply telling me to put something (the saw, the stud, or what?) in a bench vice, I politely ask you for clarification but you ignore me and instead disparage my proposed method. When I politely ask you again to explain how you would do it, you give me the above obtuse statement. Have I somehow offended you or annoyed you? If so, I apologize. I'm not a professional, so when I am working on equipment (Stihl) that professionals use, I want to ask advice of professionals on a site like Arboristsite. Perhaps you could overlook my inexperience and explain in a little more detail how to use a vice in this situation.

Thanks, Tom

 

[Anthony_Va.]

Dude, just get a pair of vise-grips or a small pipe wrench and turn the stud out. The threads are standard. Just turn it like you're taking a bolt out of the saw. Then thread the new one in by hand as far as you can and finish tightening it by either running a nut onto it, thread the nut down and use the nut to tighten it, or I have a small pipe wrench that will grip the center part of the stud that has no threads and tighten it that way.
Just snug it up good, don't overtighten it.

Fish knows what he's talking about for sure. May just be having a bad day

 

[Whiskers]

Can you get the nut off the stud or not?

 

[sefh3]

Welcome to the site. You have one of two things going on. Either the stud is stripped where the bar nuts tightens it up or the nut is bad. One this model the rear stud holds the engine block onto the saw. What I would do is go down to the Stihl dealer, order a rear bar stud and a new nut. Should cost around $15-$20. Take a pair of vise grips and remove the old stud. When you get your new stud, take a jar opener and wrap it around the collar of the stud and install it.

 

[greg409]

Tom, welcome

Your idea of double nutting a bad stud is perfectly logical - I've done it a million times on various studs (no chainsaws, but they're not special)

I agree with some to pre-buy a stud & washer since in all liklihood you'll need one or both.

As others said, snug the new stud and go on your merry way

My super xl auto had the rear stud feeling mushy, I removed, brake cleaned the weak engine case threads, shot some JB weld in it and re-inserted the stud - two days later - fixed

luck,greg